This application is based on and claims priority under 35 U.S.C. xc2xa7119 with respect to Swedish Application No. 0100317-7 filed on Feb. 1, 2001, the entire content of which is incorporated herein by reference.
1. Field of the Invention
The present invention refers to a spindle unit. More particularly, the present invention pertains to a low friction performance precision spindle unit incorporated in rotary systems.
2. Background of the Invention
Spindle units can be used in, for example, hobby articles, toys and measuring instruments. Spindle units can also be used, for example, for fishing reels to support the spool of the reel in a manner providing reliable and smooth operation while also being advantageous from the standpoint of noise aspects.
One factor for determining the quality of a fishing reel is the so-called free spool rotation time. This is defined as the time a spool will continue to rotate after it has been subjected to a defined influence. The calculation of the free spool rotation time is accomplished by attaching the reel to a fixture with the spool arranged substantially horizontal. A line of 500 mm length attached to a 20 g lead weight is affixed to the spool via a tape. The line is wound up on the spool and the weight is then dropped. The time is measured from the moment the weight is dropped until the spool has stopped rotating.
In one respect, a need exists for a spindle unit having operational properties that will provide an increased or improved time of free spool rotation to the spool of a fishing reel supported by the spindle unit.
It would also be desirable to provide an improved spindle unit having useful application in other areas where smooth low friction performance is required or desired.
According to one aspect, the precision spindle unit for low friction performance includes an elongated shaft, a tubular housing surrounding the shaft and having an interior, with the tubular housing having a larger inner diameter than the diameter of the shaft and having a first annular shoulder projecting inwardly from an inner surface of the housing, and a first rolling bearing positioned in the interior of the housing and mounted on the shaft. The first rolling bearing has an inner race ring and an outer race ring, with the inner race ring of the first rolling bearing having a first side and an oppositely located second side, and with the first side of the inner race ring of the first rolling bearing abutting against a shoulder provided on the shaft. A first locking washer is affixed to the shaft with an interference fit and is provided with an axially extending annular flange which engages the second side of the inner race ring of the first rolling bearing so that the first rolling bearing is axially arrested between the shoulder on the shaft and the annular flange on the first locking washer. A second rolling bearing is provided in the interior of the housing and has a loose fit on the shaft. The second rolling bearing includes an inner race ring and an outer race ring, with the inner race ring of the second rolling bearing having a first side facing axially outwardly and an oppositely located second side. A second locking washer is fitted with an interference fit to the shaft, and a resilient member is provided between the second locking washer and the first side of the inner race ring of the second rolling bearing. The outer race ring of the second rolling bearing has an axially inwardly directed side engaging the first annular shoulder that projects inwardly from the inner surface of the housing. The second bearing is biased under influence of the resilient member between the first annular shoulder in the housing and the resilient member. The first and the second locking washers extend radially along at least a portion of the tubular housing at a short distance from respective side faces of the housing that face the first and second locking washers to form a slot seal at each axial side of the housing, whereby each of the first and second rolling bearings at their outwardly facing sides are provided with a seal.
According to another aspect, a precision spindle unit for low friction performance includes a shaft, a tubular housing surrounding the shaft and possessing an inwardly directed first annular shoulder, and first and second rolling bearings positioned in the housing and mounted on the shaft. The first rolling bearing has an inner race ring and an outer race ring, with an axially inwardly facing side of the inner race ring of the first rolling bearing engaging a shoulder on the shaft. A first locking washer is fixed to the shaft and is provided with an axially extending annular flange which engages an axially outwardly facing side of the inner race ring of the first rolling bearing. A second locking washer is also fixed to the shaft. A resilient member is disposed between the second locking washer and the axially outwardly facing side of the inner race ring of the second rolling bearing, with the second bearing being biased between the resilient member and the first annular shoulder in the housing. The first locking washer faces a first side of the housing and is spaced from the first side of the housing by a distance forming a first labyrinth seal, and the second locking washer faces a second side of the housing and is spaced from the second side of the housing by a distance forming a second labyrinth seal.